The Center for State Fiscal Reform at the American Legislative Exchange Council (ALEC) in Arlington, Va., recently filed an amicus curiae, or "friend-of-the-court," brief with the U.S. Supreme Court on behalf of a Maryland couple, the Wynne's -- small-business owners who are being treated unfairly by Maryland tax law. The Wynne's are challenging Maryland's double-taxation policy for income earned outside of the state. The Court's decision in the case will affect state-tax policy nationwide.

Specifically, the Wynne's are challenging the fact that Maryland does not provide a full tax credit for taxes paid to other states. This means anyone in Maryland who earns money in another state must first pay that other state's income taxes, only to then have Maryland levee their county-level income taxes, without credit or deduction, on the same income -- resulting in Maryland residents being unfairly double-taxed on income they earn out of state.

ALEC believes double taxation of personal income is unconstitutional. If the Court allows it in Maryland, other states will likely amend their tax codes to remove tax credits for income taxes paid to other states -- meaning higher taxes for many Americans and a weaker economy for everyone.